Method and device for automatically triggering a deceleration in a motor vehicle

ABSTRACT

A method and a device for automatically triggering a deceleration of a vehicle so as to prevent a collision with another object. Objects in the range of the vehicle&#39;s course being detected using signals of an apparatus for sending and receiving radar signals or lidar signals, or of an apparatus for receiving video signals. An endangerment potential is determined as a function of the objects detected, and when a predefined endangerment potential theshold value, which may be less than the triggering threshold value for the deceleration, is exceeded, the deceleration means of the vehicle are reset to a state in preparation for braking. Furthermore, additional vehicle functions may be carried out when the endangerment potential threshold value is exceeded, whereby passenger safety in this travel situation is enhanced.

[0001] A method and a device are proposed for the automatic triggering of deceleration of a vehicle to prevent a collision with another object or a reduction in the consequences of an impending collision with another object, objects in the range of the vehicle's course being detected using signals of an apparatus for sending and receiving radar signals or lidar signals, or of an apparatus for receiving video signals, an endangerment potential is determined as a function of the object detected, and, as a function of the endangerment potential, the deceleration means are activated in at least three states, of which at least one state puts the deceleration means of the vehicle into a state of preparing to brake. Furthermore, other vehicle functions may be executed as a function of the endangerment potential, whereby passenger safety in this travel situation is enhanced.

BACKGROUND INFORMATION

[0002] In the past, ever more systems for distance control and speed control have come on the market, which extend the functionality of the customary vehicle-speed controller (cruise control) to the extent that when a slower, preceding vehicle is detected ahead of one's own vehicle, the speed control is switched over to a distance control, and the preceding vehicle is followed at the same speed at which it is traveling. The basic method of functioning of such distance regulating and speed regulating systems appeared in the paper “Adaptive Cruise Control System—Aspects and Development Trends”, by Winner, Witte et al., SAE Paper 96 10 10, and read at SAE International Congress and Exposition, Detroit, Feb. 26-29, 1996.

[0003] In DE 195 47 111 a method and a device for controlling the braking system of a vehicle is described, in which, even before the beginning of a wheel slip traction control, pressure is input into the wheel brakes if predefined conditions exist, no significant braking effect being applied to the drive wheels.

[0004] Essence and Advantages of the Present Invention

[0005] The essence of the present invention is to make available a method and an associated device for automatically triggering the deceleration of a vehicle to avoid a collision or reduce the consequences of an imminent collision, along with a further object. According to the present invention this is attained by the features of the independent claims, in that signals of an apparatus for sending out and receiving radar signals or lidar signals, or of an apparatus for receiving video signals, which detect objects in the range of the vehicle's course, are supplied to the device. According to the present invention, additional sensors which record the vehicle environment may also supply signals to this apparatus. In the same way, within the framework of the present invention, it is conceivable that signals from devices in the vehicle, from which the vehicle's own travel behavior may be described, may be drawn upon in this regard. Furthermore, in one endangerment potential ascertainment apparatus an endangerment potential is ascertained as a function of the detected objects, into which, for example, the probability of a collision with an object detected by the vehicle environment sensor system is entered. Advantageously, the endangerment potential is made up of a plurality of values, so that it may adequately describe the complexity of the situation to be expected. As a function of the endangerment potential, the vehicle deceleration apparatus may be prepared for the impending deceleration, in order to decrease the response time in the triggering case.

[0006] Advantageous further developments and refinements are derived from the dependent claims.

[0007] Advantageously, as a function of the endangerment potential, the deceleration devices are prepared for braking the vehicle in such a way that a braking pressure is built up in the braking system which precharges the braking system and sets the brake linings against the brake disks in such a way that no significant vehicle deceleration takes place. In the triggering case, the brake pressure may be built up substantially faster, whereby an abbreviation of the response times of the deceleration effect comes about.

[0008] Advantageously, as a function of the endangerment potential, additional vehicle functions are carried out which increase the safety of the vehicle's occupants in the case of an unavoidable collision. In this context, functions come into consideration which put the drive train of the vehicle into a state in which driving force no longer acts on the vehicle's wheels, such as, advantageously, a reduction in the engine's rotational speed to idling speed, or a deactivation of the engine by switching off the ignition system or making no further fuel injections. It should also be mentioned that the driving force transmission to the wheels may be accomplished by influencing the transmission, in that a neutral transmission stage is put in, or rather, that the transmission is set to idle.

[0009] Further advantageous functions, by which passenger safety may be enhanced, is the preparation of passenger restraint means. Reversible restraint systems, advantageously in the form of seat belt tensioners, may force the passengers into the correct sitting position, so that, in the case of an unavoidable collision, the irreversible restraint systems, advantageously in the form of airbags, may develop their full effect. In addition, as a preparing function, the triggering threshold of this irreversible restraint system may be changed, as a function of the particular driving situation and the detected object movement, in such a way that the restraint systems are triggered at the best possible time and with a force adapted to the particular situation.

[0010] Furthermore, particularly advantageous functions are informing the other traffic participants about the impending collision by advantageously switching on the hazard warning system, by activating the horn or by informing the subsequent vehicle on the imminent collision, with the aid of a radio transmission. To do this, it is essential that both one's own vehicle and the following vehicles be outfitted with an appropriate wireless communications interface.

[0011] Furthermore, it is particularly advantageous that it is provided as a function that the data flowing in before the collision, as well as those from the environmental sensor system and also those of one's own travel situation sensors be stored in a nonvolatile memory. In this way, the accident details may be cleared up after the event, but a further development of triggering algorithms for vehicle deceleration may also be carried out.

[0012] It is also advantageous if, when an unavoidable collision situation is recognized, an emergency call center or a telematic service is informed as to the instantaneous location of the vehicle and the fact that there has been a collision, which may advantageously be done with the aid of a cell phone installed in the vehicle. Thereby, help may be requested at the earliest possible point in time. It is advantageously conceivable that the informed traffic control center, emergency call center or telematic service, shortly after receiving this information, may call back the device that has dispatched the request for help, in order to confirm the occurrence of the precalculated collision and to prepare for a targeted assistance.

[0013] Implementation of the method according to the present invention in the form of a control element which is provided for a controller of an adaptive distance control and speed control is especially important. In this context, a program capable of running on a computer, in particular on a microprocessor, and suitable for execution of the method according to the present invention, is stored on the control element. Thus in this case, the present invention is implemented by a program stored on the control element, so that this control element, equipped with the program, constitutes the present invention in the same manner as the method for whose execution the program is suitable. An electric memory medium such as a read-only memory may be used in particular as the control element.

[0014] Further features, uses and advantages of the present invention come to light from the following description of exemplary embodiments of the invention which are shown in the figures of the drawings. In this context, all of the described or represented features, alone or in any combination, form the subject matter of the present invention, regardless of their combination in the patent claims or their antecedents, as well as regardless of their formulation and representation in the specification and drawings, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the following, exemplary embodiments of the present invention are explained with reference to the drawings. The figures show:

[0016]FIG. 1 a flow diagram for carrying out the method according to the present invention and

[0017]FIG. 2 a block diagram of a device for carrying out the method according to the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0018]FIG. 1 shows a flowchart of the method according to the present invention. This method is advantageously implemented in the form of a program that may be run on a microprocessor. The flow diagram is a method which, after being started, is repeated any number of times and when it reaches end A, it returns to beginning A. In step 1, data are read in from an environment sensor system with which the vehicle is equipped. For the environment sensor system, an apparatus advantageously comes into consideration for sending and receiving radar or lidar signals, or an apparatus for receiving video signals. The data read in describe objects within the range of being recorded by the sensor system, and are made up at least of the variables relative position of the object with respect to the vehicle, relative speed of the object and distance of the object from the vehicle. Additional variables which can be made available by the environment sensing system are, for instance, horizontal extension of the object, vertical extension of the object, geometry of the object or the surface nature of the area of reflection. In step 2 of the flow diagram, data are read in which describe the motions of one's own vehicle. These data originate with devices for ascertaining one's own vehicle speed, yaw rate, vehicle motion direction in relation to the longitudinal vehicle axis (attitude angle sensor), brake pedal operation, accelerator operation or steering angle sensor. In step 3 a current endangerment potential GP is determined from the data of the environment sensor system as well as from data that characterize one's own driving behavior. This endangerment potential describes the probability that a collision with an object detected by the environment sensor system is unavoidable. In subsequent step 4 a decision is made to test whether the instantaneous endangerment potential GP is greater than a predefinable threshold value SW. This threshold value SW represents the endangerment potential triggering threshold. If this is not so, this means that the endangerment potential GP lies below this endangerment potential triggering threshold SW or is equal to it, the method branches the flow diagram directly to circle A and returns to the beginning, whereupon it runs through again. If the decision in step 4 was answered “yes”, this means that the instantaneous endangerment potential GP is greater than endangerment potential triggering threshold SW, then step 5 arranges for the braking system to be prepared for an impending emergency braking or full braking, since an immediately imminent collision has to be reckoned with. According to the present invention, this preparation takes place by prefilling the braking system and causing a braking pressure buildup which is metered in such a way that the brake linings lie against the brake disks, but no significant deceleration effect occurs as yet. Along with the preparation of the braking system, additional vehicle functions are also carried out in order to enhance occupant safety in case of a collision. Additional vehicle functions to be mentioned are, that the engine is set to idling speed or the engine is deactivated, the transmission is switched to a neutral setting, so that no force transmission can take place, the reversible passenger restraint systems are activated, the triggering thresholds of the irreversible passenger restraint systems are modified so that they correspond to the current endangerment potential, a control device for controlling a braking intervention and/or an engine adjustment for stabilizing the vehicle motion is modified in such a way that it is optimized for a powerful deceleration, the other traffic participants are warned by activating the travel direction indicators and/or the horn, the subsequent vehicles are informed by a radio transmission on the impending deceleration of the vehicle, data on the detected objects in the vehicle environment and data which characterize one's own driving behavior are stored in a nonvolatile memory device, or, using radio transmission, a traffic control center or an emergency call center is informed about the vehicle position which was determined using a satellite-supported position finding method, or the two are combined.

[0019] Step 6 interrogates whether the endangerment potential GP is greater than a triggering threshold AS. This triggering threshold AS is the value which, when it is exceeded, automatically triggers a vehicle deceleration for preventing a collision with another object If the interrogation in step 6 was answered “no”, this means that the endangerment potential GP is smaller than, or equal to the triggering threshold value AS, the flow diagram branches to circle A and returns to the beginning, from where it is run through again. If it is determined in step 6 that the endangerment potential GP is greater than triggering threshold value AS, then in step 7 an automatic triggering of full braking or emergency braking takes place, so as to avoid a collision. Subsequently to step 7 the flow diagram arrives again at a circle A, from where it returns to the beginning and starts over again. It should further be mentioned that triggering threshold value AS is greater than endangerment potential threshold value SW, since the functions which prepare for deceleration should be carried out before the triggering of the deceleration itself. It should also be mentioned that the value AS and the value SW are, however, very close to each other, since false activations of the deceleration-preparing functions should be excluded to the greatest extent possible. However, when there is a rapid increase in the endangerment potential GP, sufficient time must remain between the exceeding of endangerment potential threshold value SW and the exceeding of triggering threshold value AS, so that one can carry out a complete braking preparation in the above-described manner, before initiating the deceleration. If one of action steps 5 or 7 is activated, and in the further course it turns out during a renewed cycle iteration of the method described that the activation conditions are no longer present, then a deactivation or resetting of these functions is conceivable in various ways. On the one hand, it is possible that, when a condition is no longer satisfied, a predefined time duration is allowed to pass, in which no renewed activity is allowed to occur, until the deactivation or resetting takes place. Another possibility is that endangerment potential GP has to undershoot another threshold value which is smaller than the activating threshold value, so that a resetting or deactivation of the triggered function may be undertaken.

[0020]FIG. 2 shows a device for carrying out the method described above. Device 8 for triggering of [FOOTNOTE und is superfluous] measures preparing braking as well as vehicle deceleration includes an input field 9, to which one or more input signals 12 to 13 can be supplied by sensor devices 10 to 11. As sensor devices 10 to 11, on the one hand, a radar sensor, lidar sensor or video sensor, or a combination thereof, come into consideration, as well as further apparatus whereby one's own vehicle behavior may be detected. One might name here, for example, apparatus for ascertaining one's own vehicle speed, yaw rate, vehicle motion direction, brake pedal operation, accelerator operation or a steering angle sensor, which may also be used in any combination desired. The signals arriving in input field 9 are supplied to an evaluation unit 15, using a data transport system 14. The method for triggering the vehicle deceleration so as to avoid a collision, and for triggering functions preparing for deceleration is carried out in evaluation unit 15. Depending upon the endangerment potential GP ascertained, which is determined as a function of the vehicle situation and the environmental situation, this evaluation unit 15 emits signals which are supplied to an output field 16 using data transport system 14. In one exemplary embodiment, two output signals that are able to be emitted are involved. On the one hand, a braking preparation signal, which is emitted when the decision in step 4 was answered “yes” is involved, whereupon the functions preparing braking, that were described, are activated or carried out. On the other hand, a triggering signal, which is emitted when the decision in step 6 was answered “yes” is involved, whereupon the deceleration means of the vehicle carry out a braking operation. Signals 19 to 20 are supplied via output field 16 to apparatus 17 to 18, in which further processing is carried out. In the case of apparatus 17 to 18, which have output signals 19 to 20 supplied to them, on the one hand a control unit is involved for controlling the braking system, which is able to carry out an automatic deceleration as a function of the output signals of device 8. Furthermore, apparatus 17 to 18 may involve apparatus for carrying out or triggering the measures that prepare braking,

[0021] in this instance, especially an engine control device which is able to reduce the engine speed to idling speed, or to deactivate the engine, a transmission control unit which can switch the transmission to a neutral setting, so that no force transmission can take place, a restraint system control unit which is able to activate the reversible passenger restraint systes, and which is able to modify the triggering thresholds of the irreversible passenger restraint systems in such a way that it is adjusted to the instantaneous endangerment potential. Furthermore, it is conceivable that, in the case of apparatus 17 to 18 a regulating unit is involved for controlling a braking and/or engine adjustment for stabilizing the vehicle motion, which is modified in such a way that it is optimized for a powerful vehicle deceleration, or an apparatus is involved for activating the travel direction indicators and/or the horn, so that the other traffic participants may be warned, or an apparatus for radio transmission, which is able to inform the subsequent vehicles concerning the impending deceleration of the vehicle, or a nonvolatile memory device which stores data of the detected objects in the vehicle's environment and data which characterize the driving behavior of one's own vehicle, or an apparatus for radio transmission, which informs a traffic control center or an emergency call center about the vehicle position which was determined using a satellite-supported position finding method. 

What is claimed is:
 1. A method for the automatic triggering of deceleration of a vehicle to prevent a collision with another object or a reduction in the consequences of an impending collision with another object, wherein objects in the range of the vehicle's course are detected using signals of an apparatus for sending and receiving radar signals or lidar signals, or of an apparatus for receiving video signals or a combination of these, motion variables of the vehicle are recorded, an endangerment potential is determined as a function of the objects detected and of the motion variables, and as a function of the endangerment potential ascertained, the deceleration apparatus(es) of the vehicle are controlled, the deceleration means being operated in at least three states.
 2. The method as recited in claim 1, wherein the deceleration means are operated in at least three states, in a first state the deceleration means being inactive, in a second state the deceleration means being operated in a state preparing for braking, and in a third state a deceleration being operated having a deceleration value which corresponds approximately to the maximum vehicle deceleration possible.
 3. The method as recited in claim 1, wherein the deceleration means are operated in one of four states, in a first state the deceleration means being inactive, in a second state the deceleration means being operated in a state preparing for braking, and in a third state a deceleration being carried out having a deceleration value which is clearly below the maximum vehicle deceleration possible and in a fourth state a deceleration being carried out having a deceleration value which corresponds approximately to the maximum vehicle deceleration possible.
 4. The method as recited in claim 1, wherein the deceleration means are operated in one of five states, in a first state the deceleration means being inactive, in a second state the deceleration means being operated in a state preparing for braking, in a third state a deceleration being carried out having a deceleration value which is clearly below the maximum vehicle deceleration possible, in a fourth state a deceleration being operated having a deceleration value which corresponds approximately to the maximum vehicle deceleration possible, and in a fifth state a deceleration being carried out in which the front wheels are blocked and the rear wheels remain free from being blocked.
 5. The method as recited in one of the preceding claims, wherein the state preparing for braking provides that in the braking system of the vehicle such a braking pressure is built up that the brake linings lie against the brake disks without having a significant braking effect appear.
 6. The method as recited in one of the preceding claims, wherein at least one further function is carried out as a function of the endangerment potential.
 7. The method as recited in one of the preceding claims, wherein as an additional function it is provided that the engine is reduced to idling speed or the engine is deactivated, that the transmission is switched to a neutral setting, so that no force transmission can take place, that the reversible passenger restraint systems are activated, that the triggering thresholds of the irreversible passenger restraint systems are modified so that they correspond to the current endangerment potential, that a control device for controlling a braking intervention and/or an engine adjustment for stabilizing the vehicle motion is modified in such a way that it is optimized for a powerful vehicle deceleration, that the other traffic participants are warned by activating the travel direction indicator devices and/or the horn, the subsequent vehicles are informed by a radio transmission on the impending deceleration of the vehicle, that data on the detected objects in the vehicle environment and data which characterize one's own driving behavior are stored in a nonvolatile memory device, or that, using radio transmission, a traffic control center or an emergency call center is informed about the vehicle position which was determined using a satellite-supported position finding method, or a combination thereof.
 8. A device for the automatic triggering of deceleration of a vehicle to prevent a collision with another object or a reduction in the consequences of an impending collision with another object, wherein signals, which detect objects in the range of the vehicle's course, of an apparatus for sending and receiving radar signals or lidar signals, or of an apparatus for receiving video signals, are supplied to the device; an endangerment potential is ascertained as a function of the detected objects, using an endangerment potential ascertaining device; and means for controlling vehicle deceleration devices are provided which are able to reset the deceleration means of the vehicle into a state preparing for braking when a predefined endangerment potential threshold value is exceeded which is less than the triggering threshold value for the deceleration.
 9. The device as recited in claim 8, wherein at least one further means is provided which is able to trigger additional functions as a function of the endangerment potential.
 10. The device as recited in claim 8 or 9, wherein as further means an engine control device which is able to reduce the engine speed to idling speed, or to deactivate the engine, a transmission control unit which can switch the transmission to a neutral setting, so that no force transmission takes place, a restraint system control device which is able to activate the reversible passenger restraint systems, a restraint system control device which is able to modify the triggering thresholds of the irreversible passenger restraint systems so that they are adjusted to the current endangerment potential, a control device for controlling a braking intervention and/or an engine adjustment for stabilizing the vehicle motion which is modified in such a way that it is optimized for a powerful vehicle deceleration, an apparatus for activating the travel direction indicator devices and/or the horn, so that the other traffic participants may be warned, an apparatus for radio transmission, which is able to inform the subsequent vehicles concerning the impending deceleration of the vehicle, a nonvolatile memory device which stores data of the detected objects in the vehicle'e environment and data which characterize the driving behavior of one's own vehicle, or an apparatus for radio transmission, which informs a traffic control center or an emergency call center about the vehicle position, which was determined using a satellite-supported position finding method, is provided, or a combination thereof. 